A flexible sand coating (Conniflex) for the protection of conifer seedlings against damage by the pine weevil Hylobius abietis

1 A new method for the physical protection of conifer seedlings against feeding damage by Hylobius abietis (L.), is described and evaluated in field trials in Swedish forest plantations.
2 The lower 60% of the stem of the seedling is protected by the Conniflex coating, consisting of fine sand (grain size = 0.2 mm) embedded in an acrylate dispersion that remains flexible after drying.
3 Seedlings are treated in the nursery by a large-scale application procedure involving four steps: (i) spraying the seedlings with water; (ii) application of fixative to the lower sections of the stems, (iii) application of fine sand to the fixative; and (iv) drying of the fixative.
4 A field experiment over three seasons demonstrated a significant increase in survival for coated seedlings compared with untreated seedlings. The survival rate increased from 29% to 97% for Scots pine and from 26% to 86% for Norway spruce. Coating the lower 30% of the stem (instead of 60%) provided inferior protection, resulting in only 64% survival in spruce.
5 Field trials in 11 commercial plantation areas indicated that the Conniflex sand coating was as effective in protecting seedlings as treatment with the insecticide imidacloprid.
6 The new method of coating conifer seedlings with fine sand provides an effective and environmentally sound alternative to insecticide treatment.